This invention relates to inflatable occupant restraint systems and more particularly to an inflatable occupant restraint system which releasably secures the inflatable cushion against initial deployment normal to or toward the occupant and directs such initial deployment laterally of or planar to the occupant.
By directing the initial deployment of an inflatable occupant restraint cushion laterally of or planar to the occupant, there is no engagement of the cushion and the occupant during the initial deployment stage of the cushion and such engagement is delayed to a subsequent stage of deployment.
The restraint system of this invention avoids engagement of the cushion and occupant during the initial deployment stage by releasably securing the cushion against initial deployment normal to or toward the occupant and directing such initial deployment laterally of or planar to the occupant. After initial deployment of the cushion has occurred, the securement is released and the cushion deploys normal to or toward the occupant.
The restraint system includes a known restraint module having a support, an enclosure mounted on the support, a folded occupant restraint cushion mounted on the support and located within the enclosure, and a gas generator or source of pressure fluid mounted on the support within the enclosure and communicating with the interior of the folded cushion. The cushion is folded to provide a generally planar base or upper wall portion of generally rectangular shape, a lower wall portion, fan folded longer side wall portions, and pleat folded end wall portions which are turned under the fan folded side wall portions. The side wall and end wall portions connect the upper and lower wall portions Such a restraint module is shown and described in part in copending application Ser. No. 270,609 Cok et al, Modular Occupant Restraint System, filed Nov. 14, 1988 and assigned to the assignee of this invention. The restraint system of this invention additionally includes a planar reaction member of the general size of the upper wall portion of the cushion and located within the folded cushion between the upper wall portion and the first or distal inwardly directed folds of the fan folded side wall portions. The reaction member is mounted to the support. A clamping member or securement clamps the first or distal folds of the fan folded side wall portions to the lower side of the reaction member.
During initial inflation or deployment of the cushion, the reaction member blocks impingement of the pressure fluid from the gas generator on the upper wall portion of the cushion. The clamping of the first or distal folds of the fan folded side wall portions of the cushion to the lower side of the reaction member blocks the pressure fluid from flowing between such folds and around the sides of the reaction member to the upper side thereof and underneath the upper wall portion of the cushion. The pleat folded end wall portions provide a tortuous path and effectively block the pressure fluid from flowing around the ends of the reaction member to the upper side thereof. Thus, no pressure fluid can impinge on the upper wall portion and the upper wall portion remains stationary during the initial stage of deployment of the cushion. The impingement of the pressure fluid against the fan folded side wall portions of the cushion, other than the first or distal folds, initiates deployment of the cushion laterally of or planar to the occupant through outwardly opening separable flaps in the side walls of the enclosure opposite the side wall portions of the cushion. As the pressure and volume of the pressure fluid build up within the cushion, the fan folded side wall portions continue to unfold. When the volume and pressure of the pressure fluid reach a level sufficient to overcome the clamping force of the clamping member, the first or distal folds of the cushion are pulled outwardly and away from the lower side of the reaction member to permit the pressure fluid to impinge on the upper wall portion of the cushion around the reaction member as the distal folds unfold relative to the side and upper wall portions. The impingement of the pressure fluid on the upper wall portion initiates deployment of the cushion through outwardly opening separable flaps in the upper wall of the enclosure as the pleat folded end wall portions unfold, to provide the upper or outer wall of the cushion which moves normal to or toward the occupant. The subsequent engagement of the occupant and such upper or outer wall during such movement provides the occupant restraint.
The primary feature of this invention is that it provides an occupant restraint system which releasably secures an inflatable occupant restraint cushion against movement normal to or toward an occupant during the initial stage of deployment of the cushion. Another feature is that the cushion is deployed in directions laterally of or planar to the occupant during the initial deployment stage. A further feature is that the wall of the cushion engageable by the occupant is releasably secured against movement normal to or toward the occupant during the initial deployment stage. Yet another feature is that such wall of the cushion is released when the volume and pressure of the inflating pressure fluid build up to a predetermined level. Yet a further feature is that the cushion is folded to provide a base or upper wall portion, fan folded side wall portions and pleat folded end wall portions, with the distal folds of the fan folded side wall portions being releasably clamped to a reaction member. Still another feature is that the reaction member is planar, of the general size of the upper wall portion of the folded cushion, and has its upper side engaging such upper wall portion and its lower side clamped to the distal folds of the fan folded side wall portions. Still a further feature is that the reaction member is mounted to the support for the cushion. Yet another feature is that the clamping force is provided by a clamping member mounted to the lower side of the reaction member.